On Tue, Dec 17, 2013 at 05:30:02PM -0700, Bjorn Helgaas wrote: > After this patch, we would have: > > pci_enable_msi() # existing (1 vector) > pci_enable_msi_block(nvec) # existing > pci_enable_msi_block_auto(maxvec) # existing (removed) > > pci_auto_enable_msi(maxvec) # new (1-maxvec) > pci_auto_enable_msi_range(minvec, maxvec) # new > pci_auto_enable_msi_exact(nvec) # new (nvec-nvec) > > pci_enable_msix(nvec) # existing > > pci_auto_enable_msix(maxvec) # new (1-maxvec) > pci_auto_enable_msix_range(minvec, maxvec) # new > pci_auto_enable_msix_exact(nvec) # new (nvec-nvec) > > That seems like a lot of interfaces to document and understand, especially > since most of them are built on each other. I'd prefer just these: > > pci_enable_msi() # existing (1 vector) > pci_enable_msi_range(minvec, maxvec) # new > > pci_enable_msix(nvec) # existing > pci_enable_msix_range(minvec, maxvec) # new > > with examples in the documentation about how to call them with ranges like > (1, maxvec), (nvec, nvec), etc. I think that will be easier than > understanding several interfaces. I agree pci_auto_enable_msix() and pci_auto_enable_msix_exact() are worth sacrificing for the sake of clarity. My only concern is people will start defining their own helpers for (1, maxvec) and (nvec, nvec) cases here and there... > I don't think the "auto" in the names really adds anything, does it? The > whole point of supplying a range is that the core has the flexibility to > choose any number of vectors within the range. "Auto" indicates auto-retry, but I see no problem in skipping it, especially if we deprecate or phase out the existing interfaces. > I only see five users of pci_enable_msi_block() (nvme, ath10k, wil6210, > ipr, vfio); we can easily convert those to use pci_enable_msi_range() and > then remove pci_enable_msi_block(). > > pci_enable_msi() itself can simply be pci_enable_msi_range(1, 1). > > There are nearly 80 callers of pci_enable_msix(), so that's a bit harder. > Can we deprecate that somehow, and incrementally convert callers to use > pci_enable_msix_range() instead? Maybe you're already planning that; I > know you dropped some driver patches from the series for now, and I didn't > look to see exactly what they did. Right, the plan is first to introduce pci_auto_* (or whatever) family into the tree and then gradually convert all drivers to the new interfaces. > It would be good if pci_enable_msix() could be implemented in terms of > pci_enable_msix_range(nvec, nvec), with a little extra glue to handle the > positive return values. [...] > I think it would be better to make pci_enable_msix_range() the fundamental > implementation, with pci_enable_msix() built on top of it. That way we > could deprecate and eventually remove pci_enable_msix() and its tri-state > return values. We can reuse pci_enable_msix() name, but not before all drivers converted. But considering the other thread you want to have only pci_enable_msi_range() and pci_enable_msix_range() interfaces - am I getting it right? -- Regards, Alexander Gordeev agordeev@xxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
